Whisk honey, 1 tablespoon lemon juice, shallot, 1 1/2 teaspoon olive oil and 1/4 teaspoon lemon zest together in a shallow baking dish. Add salmon fillets and turn to coat. Cover and refrigerate until flavours combine, 15 minutes to 1 hour.
Whisk creme fraiche, 1 1/2 teaspoon lemon juice, 1/4 teaspoon lemon zest, salt and pepper together in a small bowl to make a sauce.
Toss watercress, dill and tarragon with 2 teaspoons lemon juice and 2 teaspoons olive oil in a bowl to make salad. Season with salt and pepper.
Set an oven rack in the top part of the oven and preheat to 200 C / Gas 6. Line a baking tray with foil; brush with remaining 1 teaspoon olive oil.
Transfer salmon fillets, with marinade, to the prepared baking tray.
Bake in the preheated oven until salmon is just opaque in the centre, about 15 minutes.
Serve salmon with some salad and sauce on top. Serve remaining sauce on the side. Garnish with lemon wedges.